This invention relates in general to prefabricated buildings and, more particularly, to a building that utilizes preferably prefabricated, cold formed steel wall panels and prefabricated, hollow core concrete floor slabs. When completed, the prefabricated walls and floor slabs provide a structural support system for the building. The invention also relates to methods for fabricating and erecting such a support system.
In low rise multi-story buildings having steel structural support systems, prefabricated light weight steel framing (L.W.S.F.) is predominately used. The basic building component of light weight steel framed structures is the cold formed shape. The use of light weight steel framing was heavily influenced by wood framing. The "2 by" member, e.g., "2.times.4", of wood framing was simply replaced with a cold formed "C" or "Z" shaped, thin steel section. In building design, prefabricated, light weight steel framed wall panels are divided essentially into two categories: (1) curtain wall and (2) load bearing. Curtain wall studs are flexural members used in non-bearing, exterior wall panels that are designed to resist only wind loads, axial loads due to the weight of the curtain wall itself and the weight of finishes only. These members provide structural support for a variety of exterior finishes including masonry veneer, stucco, synthetic veneers and exterior insulation with finish systems. Interior finishes such as gypsum wall board may be attached directly to the light weight steel framing. A typical curtain wall detail is shown in FIG. 1, which illustrates an application of a known wind bearing stud wall having a window opening. The stud wall shown in FIG. 1 is arranged between floor slabs 1 and 2. Wind non-bearing wall studs 3 extend between the floor slabs. The bottom of each wall stud is located in a bottom track 4 while the top of the stud is located in an inner track 5, which is received within an outer top track 6. Top track 6 typically is connected to floor slab 2 by drilled expansion anchors (not shown). Window head 7, jamb stud 9, and window sill 8 form a window opening.
A total load bearing system constructed from light weight steel framing includes studs and joists. A load bearing stud is designed to support axial and wind loads while a joist is designed to support the interior dead load and live load of the building. A known type of construction for a light weight steel framed building comprised of axial load bearing studs, joists, and rafters is illustrated in FIG. 2, which shows typical details for platform type construction. In platform type construction each floor acts as a working platform for the construction of the next story. The building shown in FIG. 2 is a two story building which includes a bottom floor joist 1' and a top floor joist having a stair opening 2' formed from a tail joist, header joist, and trimmer joist reinforced to suit the opening. Axial load bearing studs 3' are located between the top and bottom tracks 4', 5' respectively. Concrete stops or subfloor edge supports 6' are arranged at the inner side of the bottom tracks for defining the ends of a floor, which may be constructed from plywood or poured concrete. Cross bracing 7' is illustrated, as well as a ceiling joist 8' and roof rafter 9'. The bridging for the ceiling joist and roof rafter is not shown. FIG. 3 illustrates a typical platform framing detail for an exterior floor to bearing wall intersection of the building illustrated in FIG. 2. Studs 3' have "C" shaped cross sections defined by a web 12', two flanges 13' connected to the ends of the web and lips 14' connected to the free ends of the flanges 13' to stiffen the flanges. A closure channel 6' and web stiffener 10' also are illustrated in FIG. 3. The same detail using typical balloon framing is illustrated in FIG. 4. A ledger angle 11' is used to support the floor joist 1' during erection.
In low rise concrete buildings, the hollow core slab system of construction has been used. The basic component of the hollow core slab system of construction is a prefabricated, prestressed concrete member or slab having a series of continuous voids. The slabs may be arranged to form walls, floors, roof decks and spandrel panels. Hollow core slabs are most widely known for providing economical floor and roof systems. The most common use of hollow core slab is found in "block and plank" structures where the prefabricated, hollow core slabs form the floors and roof, which are supported by concrete block walls. Finishes may be applied directly to the top and/or underside surface of the hollow core slabs. FIGS. 5-8 illustrate the use of known hollow core slab and concrete block construction.
The continually rising cost of building construction and the longstanding need for affordable housing have motivated the building design community to consider alternative construction materials and methods of constructing low rise multi-story buildings. In the past, the use of steel structures or concrete structures, such as those described above, have dominated the building industry.